I need a validation that takes either a dropdown list with an indirect(A1)
reference off of one cell in the case that a second cell has "internal" in
it, or an "any value" validation if that second cell says "external".
Example:

A B C
1 test external
2 bed internal
3 test internal

C1 should validate to any value the use wants to put in
C2 should validate to a dropdown list with the values from named range "bed"
c3 should validate to a dropdown list with values from named range "test"

Any way to accomplish this?
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Boris